Micromachining can be difficult to apply to many engineering materials due to a variety of scaling induced factors including: low cutting speeds, high relative tool deflections and runout, and increased material strength at smaller size scales. Additionally, edge burrs which can easily be removed after macro-scale machining must be avoided in micromachining due to the lack of available finishing operations. A fundamental change in the cutting process occurs when the uncut chip thickness falls below a minimum value. Below this minimum chip thickness the work material is ploughed by the tool instead of being cleanly sheared away, resulting in increased cutting forces, surface roughness, and a decrease in machined edge quality. Some hard materials such as ceramics and high temperature alloys will further increase the wear on the cutting tool.
Specific cutting energy at the micro-scale is much higher than at the macro-scale owing to the well known size-effect in machining operations and the relative dullness of micro tools. This dullness is due to limits on how small the cutting edge radius can be made. Typically, conventional machining systems have an edge radius to diameter ratio of 1×10−6 while micromachining systems often has a ratio greater than 0.005. These issues result in higher relative cutting forces which cannot be sustained by micro-sized cutting tools. For micromachining systems this typically leads to failure of the tool by complete fracture at the flute starting location.
Therefore, there is a need for a laser-assisted micromachining system which can precisely cut hard objects while maintaining a high edge quality and decreasing the wear on a cutting tool to achieve prolonged tool life.